To date our attempts to assess the effectiveness of lecithin for the treatment of patients with tardive dyskinesia have been plagued by methodologic difficulties. After several years' work with preparations of lecithin containing leser quantitites of phosphatidyl choline (PC) --20% and 55%, we began to use a preparation that was 80%-100% pure. Although we decreased the quantity administered to patients to compensate for the increased PC percentage, several patients who had previously been maintained on a lower-grade lecithin preparation developed new adverse effects, namely parkinsonian signs. Because of uncertainty as to the nature of these reactions, we discontinued lecithin in these patients. Moreover, our recruitment of new patients to participate in this project has been hampered by the nature of the lecithin itself. The current preparation comes in a paraffin-like form, which requires careful refrigeration and daily preparation in a blender. This has rendered it unsatisfactory for a majority of schizophrenic outpatients whom we have attempted to recruit, which has impaired patient intake into the study. As a consequence, we are currently returning to a lower-grade lecithin preparation, containing 55% PC, but which is available in granule form, which can be mixed into or sprinkled on food.